PORTLAND, Maine — A storm that caused havoc in the South brought wacky weather to northern New England on Thursday with thick fog, heavy rain, record warmth, ice jams and wind gusts topping 70 mph that caused numerous power outages. It was capped off with a pendulum swing back to colder temperatures.

Across northern New England, powerful wind gusts knocked out electricity for more than 70,000 homes and businesses, mostly in Maine, while warm temperatures and heavy rainfall caused ice jams on many rivers, threatening a number of communities, including Montpelier.

Several ski areas shut down for the day because of rain, or strong winds, or both.

In Maine, the wind gusted to 63 mph in Bath, ripping part of the roof off the Maine Maritime Museum. Gusts also hit 54 mph in Augusta, and 49 mph at the Portland International Jetport.

Offshore, the wind hit 60 mph at New Hampshire’s Isles of Shoals and 74 mph at Maine’s Matinicus Rock.

“That’s natural for us,” said Wanda Philbrook, post master on Matinicus Island, which is 20 miles from the coast of Maine. “It’s just another day in paradise.”

The day started with rain and heavy fog that gave way to sun and a second day of warm temperatures. In Portland, the temperature hit 54 degrees, tying the record for the date for the second consecutive day. By midnight, the temperature was expected to drop below freezing, plummeting more than 30 degrees.

By 2 p.m. Thursday, the temperature was about 12 degrees atop New Hampshire’s Mount Washington, the highest peak in the Northeast and home to some of the world’s most erratic weather.

By contrast, it reached 43 degrees at the summit on Wednesday, breaking the previous record of 38 set in 1947. Before temperatures started falling Thursday, the 38-degree reading at midnight broke the record for the day of 35 set in 1947.

All of that warm weather and rain caused rivers to rise and ice to break up, forming ice jams that raised the threat of localized flooding. In Maine, an ice jam closed the Route 4 bridge in Madrid.

In Montpelier, city officials warned residents to be on alert after an ice jam that broke loose from the Berlin area threatened the Winooski River.

Eventually, the threat to Montpelier subsided, but there were flood warnings on at least a half-dozen rivers, including the Saco River at Conway, N.H.

The cause of the wacky weather was the same winter weather system that spawned tornadoes in southern states, said Margaret Curtis from the National Weather Service.

In the south, two people were killed by tornadoes Tuesday and Wednesday, while a third was found dead Thursday in a flooded homeless camp in Maryland.

In northern New England, the biggest problem was the wind, which knocked down trees and tree limbs. The largest number of power outages were in Maine, where Central Maine Power reported more than 40,000 and Bangor Hydro Electric Co. reported more than 20,000 at the height of the storm. More than 13,000 power outages were reported in New Hampshire.